Pulse

By GCN Staff

L.A. synchronizes traffic signals, but drivers might not notice

Few commuters stuck in big city traffic haven’t thought about sending a note to city hall complaining about slow traffic lights, especially during rush hour. If only the city could tighten up traffic signal synchronization, that would speed things up. So most people would think, anyway.

Well now there is definitive proof. The city of Los Angeles finished work just last month on the Automatic Traffic Surveillance and Control system, a $400 million effort to computerize its entire traffic management system.

First started 30 years ago to help improve traffic around L.A. in preparation for the 1980 Olympic Games, the system today controls the synchronization of each one of the city’s 4,500 traffic lights that handle the flow of 7 million commuters each day.

Regulating the signals is done through magnetic sensors planted at every intersection, which in turn are connected to a control center in downtown L.A. The system analyzes both past traffic data flowing through the network as well as real-time data to automatically regulate the signals, according to a report in the Los Angeles Times.

But is the system improving commuting times for the average L.A. citizen? The best answer might be ... yes, somewhat. The average speed of traffic has moved from 15 miles per hour to 17.3 miles per hour on a citywide basis, according to the city’s transportation department. Delays at intersections are down 12 percent, according to the report, which described the difference as a “smoother kind of slow.”

Why hasn’t the system cut traffic congestion more dramatically? For one thing there are more people poring into the city on a daily basis, with the overall population increasing about 20 percent since 198o. Another factor is that improved traffic speed leads to more people traveling, University of Southern California civil engineering professor James Moore told the New York Times. The “benefit is not speed, it’s throughput,” he said.

So might these findings appeal to other cities? Government workers in the Washington, D.C., area might have a chance to find out. The city is “considering” buying the ATSC software from Los Angeles, according a report in the New York Times.